[Radioguy52]

Just found this Philco 46-420 Code 121:  Thanks to this forum I was able to retrieve the Philco Service Schematics.. But curious I could never find these schematics in either Beitmans nor Riders?  Any historical significance?  Also any handy tips on removal of this chasis without messing up the dial cord?

[Kestas]

Here is a copy of the Riders Philco 46-420 Code 121.  Double check that it matches what you have.  The Hippo models came with different chasses.

The dial cord will need to be disconnected to work on the chassis.  It's not that big a deal. Make good notes to where the antenna connections go before unsoldering them.

[Radioguy52]

Thank you.. I now see it is in the volume 15 Riders. Missed it in my original search . seems like it just missed the next series of volumes.. Thank you. It is strange that Beitmans not showing in 1946 or 1947

[RodB]

Beitman schematics are for the "Most Popular" radio models for that year. So, a 1946 Philco model may show up in the 1948 Beitman catalog if it didn't become popular till 1948. Have no idea what criteria they used to put a specific model in. It's nice to find your radio in there because they are good copies, often much better than Rider. BTW I looked at my Beitman index and your radio is not listed.

[Ron Ramirez]

Why even consider Rider vs. Beitman when the best possible service info for the 46-420 - factory service data - is available here, and for free?

[Paul Philco322]

Free is good, especially in this hobby,

Paul

[Radioguy52]

I agree.. I was just curious. The 1946 Beitmans has NO Philcos.. was thinking it had some patent issue or maybe WWII.. But yes the Philco Bulitins are best.

[Radioguy52]

Restoration Update. This radio has a "partial" upgrade to a PM Speaker. The upgrade has a 4inch speaker . The substitue resistors for the original speaker choke did not happen. Instead there is a transformer attached to the bottom in place of the original speaker choke. and 2 30 UF Electrolytics vs the original 20Uf.

Tubes. Of the 6 3 tested good 50, 35, and 7A8 Tube 7B7 test bad. 7C7 50% and 7C6 50%

Question prices quite high on eSlay for the 7B7 but I read the 7A7 is a suitable sub? is thatacurate?

[Ron Ramirez]

Bob Dobush at FindATube.com has NOS/NIB 7B7 tubes for $7 each; used, tested 7B7s for $3.50.

7A7 is listed as a substitute for the 7B7 according to the NJ7P tube database. Bob has them for $3.00 new, $1.50 used.

[Radioguy52]

Here is a picture of the chasis with 2 transformers .. Radio has a PM

[Mondial]

I would not recommend the 7A7 as a sub for the 7B7 in a filament series string AC-DC radio. The 7B7 has a 0.15 Amp filament while the 7A7 has a 0.3 amp filament. While the sub would work fine in a transformer powered set, the 7A7 filament would not heat properly in a series connection with other 0.15 Amp filament tubes.

Better to stick with the correct 7B7.

[Radioguy52]

Thanks: I am pursuing exact RR.. Ron sent a link to Find a tube.. Hopefuly I can source ... This is a great forum..

[David]

Might be able to sub a 14A7.    https://frank.pocnet.net/sheets12.html   Price is something I could live with.     Remember doing this many years ago and it worked can not recall the set. Hope this helps David    https://vacuumtubesinc.com/index.php/14a7-12b7.html

[Ron Ramirez]

Mondial is right about the 7A7 - I didn't make an exhaustive search for a sub, just a quick one.

[Radioguy52]

David: Regarding the 14A7.. Do I have any mods to make to account for filiment voltage?